DARPA has 58 pages of specifications around what kind of flying car they want.
* flying/driving range of 250 miles
* measure no more than 30 feet long by 8.5′ wide and 9′ high
* perform vertical take-off and landing
* carry four people
* perform unmanned operations
* and be easy enough to control that anyone who can drive a Humvee can also pilot the vehicle.
* Capable of handling small arms fire
* Quick entry and exit

Logi Aerospace plans the Tyrannos, which will bea 4-rotor, 4-wheeled, folding wing, Vertical Takeoff or Landing (VTOL), roadable air vehicle. Primary power is supplied via an air-breathing engine coupled to a generator. Secondary power comes from a battery pack. Electric motors drive each of the shrouded propellers and each of the wheels (8 motors in total).

The first obvious thing, as one views the vehicle, is the lack of duct area. Using non-optimized ducts brings about over a 100% increase in duct area for this 3,000 lb vehicle, resulting in an approximate 66% increase in vehicle gross weight as the effects ripple through the design. Trek Aerospace’s shrouded propeller technology, was independently developed over the last decade and validated with both DARPA and NASA test programs. It is a breakthrough.

This is not just an ordinary shroud or nacelle around the propellers. This shroud has been specifically designed to optimize airflow. The result – at takeoff, nearly half the lift is provided by the shroud and not the propellers. This means the propellers cover only half the area of a helicopter and still lift the same amount of vehicle weight.

This also means the propellers are lighter and smaller, so too, are the wings and structures making the vehicle lighter. A lighter vehicle can be flown with a smaller propeller, which makes the wings, the structure and the whole vehicle lighter. It has an iterative effect on the design and scales the vehicle down in size. This scale reduction means our vehicles can often be built for less than half the empty weight, and cost, of other vehicles that don’t have our shroud technology. This also means, that on average, our vehicles have around 1/3 of the propeller area of other vehicles that carry our payload using non-optimized shrouds. This is because our shroud is more efficient and the vehicle at takeoff is lighter

Sky Driving on Imaginary Freeways

The Tyrannos actually flies itself along a path designated by the operator. There are two ways you can designate how to guide the vehicle.

First, you simply pull gently on the “up” paddle on the backside of the steering wheel and the “road” shown on your windshield will begin a gradual “uphill” rise along a freeway ramp. At the same time, you will press on the gas and accelerate up the freeway ramp. When you reach the altitude you’d like to fly at, simply let up on the “up” paddle and the “freeway” will level out on the windshield.

If you would like to turn, then simply turn the wheel of the car and the road on your windshield will bend in the same direction much like a curve on a freeway. The car will follow the path you designate using the steering wheel and “up/down” paddles.

To slow down and descend, you simply press on the brake or set the cruise control at your descent speed and then pull on the opposite paddle on the backside of the steering wheel. The road descends with the same steepness as a typical freeway ramp.

In the future, the FAA will designate freeways in the sky and exit ramps will be the same as on a normal freeway cloverleaf exit, except the curves will be bigger since the vehicle is going 50% to 110% faster than cars on a freeway.

Secondly, you can design and load a mission route and the aircraft will fly itself using an auto takeoff, autopilot and auto land capability. This capability requires non-FAA airspace specially designated for autonomous unmanned aerial vehicles. Now, you can only find this in military ranges and combat zones. In the future the FAA may allow this type of flight for commercial use.